Tarpaulins, also known as “tarps,” are primarily used as protective covers for piles of material or stacks of objects. However, they are also commonly used to haul materials across the ground. For example, after raking or blowing leaves, landscapers frequently use tarps, to collect the leaves and transport them for disposal. Tarps can also be used to transport other landscaping debris such as sticks and other plant matter, as well as soil, mulch and various other materials. A large tarp, e.g., a 3.5×2.5 meter rectangular tarp, can be used to haul a quantity of material equivalent to as many as five to ten wheelbarrow loads.
Tarps are manufactured from a wide variety of materials. A tarp used for hauling is typically composed of a nylon-fiber-reinforced vinyl sheet. Typical landscaping tarps are described in the following U.S. Pat. No. 2,974,971, granted to H. H. Buck on Mar. 14, 1961; U.S. Pat. No. 3,355,187, granted to M. Brindle on Nov. 28, 1967; U.S. Pat. No. 5,104,133, granted to D. Reiner on Apr. 14, 1992; U.S. Pat. No. 5,529,321, granted to G. Thompson on Jun. 25, 1996; U.S. Pat. No. 5,660,402, granted to E. Jones et al. on Aug. 26, 1997; U.S. Pat. No. 5,943,831, granted to W. Pangburn on Aug. 31, 1999; and U.S. Pat. No. 6,565,101, granted to B. Jones et al. on May 20, 2003.
When a tarp is used to haul materials such as landscaping debris, it is dragged along the ground, and friction and abrasion between the tarp and the surface on which it is dragged can cause rapid deterioration of the tarp. Depending on the material from which it is made, and the manner in which it is used, the tarp can reach the point at which it is no longer useful in a few weeks, or even a few days.
One solution to the problem of deterioration by abrasion is to use a sled-like device instead of a tarp. One such device is described in U.S. Pat. No. 4,173,351, granted to Philip R. Hetland on Nov. 6, 1979. Another such device is described in U.S. Pat. No. 5,211,434, granted to Santo M. Lanava on May 18, 1993. Still another sled-like device is described in U.S. patent application publication 2005/0263998, published on Dec. 1, 2005. A difficulty with such a sled-like device is that, if it is large enough to hold several wheelbarrow loads of material, it cannot be stored easily, and cannot be transported easily on a landscaper's vehicle.
Our U.S. Pat. No. 8,091,937, granted Jan. 10, 2012, addresses the problem of storage by providing a tarpaulin with plural rigid glides attached to a flexible sheet and positioned on the flexible sheet at locations such that the sheet can be folded on fold lines extending between the glides. More particularly, the tarpaulin of U.S. Pat. No. 8,091,937 comprises a flexible, foldable, sheet having opposite front and back edges spaced from each other in a lengthwise direction, opposite side edges spaced from each other in a widthwise direction, a top face and a bottom face. The top side of each of a plurality of substantially rigid synthetic resin glides, each having a top side and a bottom side, are attached to the bottom face of the sheet, and the bottom sides of the glides are sufficiently smooth to enhance sliding of the sheet on a supporting surface. The glides are spaced from one another in an array such that the sheet can be folded on itself along fold lines extending between adjacent glides from one edge of the sheet to an opposite edge of the sheet. A central portion of the bottom side of each of the glides is convex, and surrounded by a rim which is unitary with the central portion. The rim of each glide is in facing relationship with a part of the flexible, foldable sheet, and secured against movement relative to the part of the flexible, foldable sheet with which it is in facing relationship.
The tarpaulin of U.S. Pat. No. 8,091,937 is both highly durable and easily folded for storage. However, the convex shape of the central part of each of the glides, and the need to attach a rim of each of the glides to the flexible sheet, makes manufacture of the tarpaulin expensive.